3 use syntax::ast::{self, Ident};
5 use syntax::source_map::{ExpnInfo, ExpnKind, respan};
6 use syntax::ext::base::{ExtCtxt, MacroKind};
7 use syntax::ext::build::AstBuilder;
8 use syntax::ext::expand::ExpansionConfig;
9 use syntax::ext::hygiene::ExpnId;
10 use syntax::mut_visit::MutVisitor;
11 use syntax::parse::ParseSess;
13 use syntax::symbol::Symbol;
14 use syntax::symbol::{kw, sym};
15 use syntax::visit::{self, Visitor};
17 use syntax_pos::{Span, DUMMY_SP};
19 const PROC_MACRO_KINDS: [Symbol; 3] = [
20 sym::proc_macro_derive,
21 sym::proc_macro_attribute,
25 struct ProcMacroDerive {
26 trait_name: ast::Name,
29 attrs: Vec<ast::Name>,
37 struct CollectProcMacros<'a> {
38 derives: Vec<ProcMacroDerive>,
39 attr_macros: Vec<ProcMacroDef>,
40 bang_macros: Vec<ProcMacroDef>,
42 handler: &'a errors::Handler,
43 is_proc_macro_crate: bool,
47 pub fn modify(sess: &ParseSess,
48 resolver: &mut dyn (::syntax::ext::base::Resolver),
49 mut krate: ast::Crate,
50 is_proc_macro_crate: bool,
51 has_proc_macro_decls: bool,
53 num_crate_types: usize,
54 handler: &errors::Handler) -> ast::Crate {
55 let ecfg = ExpansionConfig::default("proc_macro".to_string());
56 let mut cx = ExtCtxt::new(sess, ecfg, resolver);
58 let (derives, attr_macros, bang_macros) = {
59 let mut collect = CollectProcMacros {
61 attr_macros: Vec::new(),
62 bang_macros: Vec::new(),
68 if has_proc_macro_decls || is_proc_macro_crate {
69 visit::walk_crate(&mut collect, &krate);
71 (collect.derives, collect.attr_macros, collect.bang_macros)
74 if !is_proc_macro_crate {
78 if num_crate_types > 1 {
79 handler.err("cannot mix `proc-macro` crate type with others");
86 krate.module.items.push(mk_decls(&mut cx, &derives, &attr_macros, &bang_macros));
91 pub fn is_proc_macro_attr(attr: &ast::Attribute) -> bool {
92 PROC_MACRO_KINDS.iter().any(|kind| attr.check_name(*kind))
95 impl<'a> CollectProcMacros<'a> {
96 fn check_not_pub_in_root(&self, vis: &ast::Visibility, sp: Span) {
97 if self.is_proc_macro_crate && self.in_root && vis.node.is_pub() {
98 self.handler.span_err(sp,
99 "`proc-macro` crate types cannot \
100 export any items other than functions \
101 tagged with `#[proc_macro_derive]` currently");
105 fn collect_custom_derive(&mut self, item: &'a ast::Item, attr: &'a ast::Attribute) {
106 // Once we've located the `#[proc_macro_derive]` attribute, verify
107 // that it's of the form `#[proc_macro_derive(Foo)]` or
108 // `#[proc_macro_derive(Foo, attributes(A, ..))]`
109 let list = match attr.meta_item_list() {
113 if list.len() != 1 && list.len() != 2 {
114 self.handler.span_err(attr.span,
115 "attribute must have either one or two arguments");
118 let trait_attr = match list[0].meta_item() {
119 Some(meta_item) => meta_item,
121 self.handler.span_err(list[0].span(), "not a meta item");
125 let trait_ident = match trait_attr.ident() {
126 Some(trait_ident) if trait_attr.is_word() => trait_ident,
128 self.handler.span_err(trait_attr.span, "must only be one word");
133 if !trait_ident.name.can_be_raw() {
134 self.handler.span_err(trait_attr.span,
135 &format!("`{}` cannot be a name of derive macro", trait_ident));
138 let attributes_attr = list.get(1);
139 let proc_attrs: Vec<_> = if let Some(attr) = attributes_attr {
140 if !attr.check_name(sym::attributes) {
141 self.handler.span_err(attr.span(), "second argument must be `attributes`")
143 attr.meta_item_list().unwrap_or_else(|| {
144 self.handler.span_err(attr.span(),
145 "attribute must be of form: `attributes(foo, bar)`");
147 }).into_iter().filter_map(|attr| {
148 let attr = match attr.meta_item() {
149 Some(meta_item) => meta_item,
151 self.handler.span_err(attr.span(), "not a meta item");
156 let ident = match attr.ident() {
157 Some(ident) if attr.is_word() => ident,
159 self.handler.span_err(attr.span, "must only be one word");
163 if !ident.name.can_be_raw() {
164 self.handler.span_err(
166 &format!("`{}` cannot be a name of derive helper attribute", ident),
176 if self.in_root && item.vis.node.is_pub() {
177 self.derives.push(ProcMacroDerive {
179 trait_name: trait_ident.name,
180 function_name: item.ident,
184 let msg = if !self.in_root {
185 "functions tagged with `#[proc_macro_derive]` must \
186 currently reside in the root of the crate"
188 "functions tagged with `#[proc_macro_derive]` must be `pub`"
190 self.handler.span_err(item.span, msg);
194 fn collect_attr_proc_macro(&mut self, item: &'a ast::Item) {
195 if self.in_root && item.vis.node.is_pub() {
196 self.attr_macros.push(ProcMacroDef {
198 function_name: item.ident,
201 let msg = if !self.in_root {
202 "functions tagged with `#[proc_macro_attribute]` must \
203 currently reside in the root of the crate"
205 "functions tagged with `#[proc_macro_attribute]` must be `pub`"
207 self.handler.span_err(item.span, msg);
211 fn collect_bang_proc_macro(&mut self, item: &'a ast::Item) {
212 if self.in_root && item.vis.node.is_pub() {
213 self.bang_macros.push(ProcMacroDef {
215 function_name: item.ident,
218 let msg = if !self.in_root {
219 "functions tagged with `#[proc_macro]` must \
220 currently reside in the root of the crate"
222 "functions tagged with `#[proc_macro]` must be `pub`"
224 self.handler.span_err(item.span, msg);
229 impl<'a> Visitor<'a> for CollectProcMacros<'a> {
230 fn visit_item(&mut self, item: &'a ast::Item) {
231 if let ast::ItemKind::MacroDef(..) = item.node {
232 if self.is_proc_macro_crate && attr::contains_name(&item.attrs, sym::macro_export) {
234 "cannot export macro_rules! macros from a `proc-macro` crate type currently";
235 self.handler.span_err(item.span, msg);
239 // First up, make sure we're checking a bare function. If we're not then
240 // we're just not interested in this item.
242 // If we find one, try to locate a `#[proc_macro_derive]` attribute on it.
243 let is_fn = match item.node {
244 ast::ItemKind::Fn(..) => true,
248 let mut found_attr: Option<&'a ast::Attribute> = None;
250 for attr in &item.attrs {
251 if is_proc_macro_attr(&attr) {
252 if let Some(prev_attr) = found_attr {
253 let msg = if attr.path.segments[0].ident.name ==
254 prev_attr.path.segments[0].ident.name {
255 format!("only one `#[{}]` attribute is allowed on any given function",
258 format!("`#[{}]` and `#[{}]` attributes cannot both be applied \
259 to the same function", attr.path, prev_attr.path)
262 self.handler.struct_span_err(attr.span, &msg)
263 .span_note(prev_attr.span, "previous attribute here")
269 found_attr = Some(attr);
273 let attr = match found_attr {
275 self.check_not_pub_in_root(&item.vis, item.span);
276 let prev_in_root = mem::replace(&mut self.in_root, false);
277 visit::walk_item(self, item);
278 self.in_root = prev_in_root;
285 let msg = format!("the `#[{}]` attribute may only be used on bare functions",
288 self.handler.span_err(attr.span, &msg);
292 if self.is_test_crate {
296 if !self.is_proc_macro_crate {
297 let msg = format!("the `#[{}]` attribute is only usable with crates of the \
298 `proc-macro` crate type", attr.path);
300 self.handler.span_err(attr.span, &msg);
304 if attr.check_name(sym::proc_macro_derive) {
305 self.collect_custom_derive(item, attr);
306 } else if attr.check_name(sym::proc_macro_attribute) {
307 self.collect_attr_proc_macro(item);
308 } else if attr.check_name(sym::proc_macro) {
309 self.collect_bang_proc_macro(item);
312 let prev_in_root = mem::replace(&mut self.in_root, false);
313 visit::walk_item(self, item);
314 self.in_root = prev_in_root;
317 fn visit_mac(&mut self, mac: &'a ast::Mac) {
318 visit::walk_mac(self, mac)
322 // Creates a new module which looks like:
326 // extern crate proc_macro;
328 // use proc_macro::bridge::client::ProcMacro;
330 // #[rustc_proc_macro_decls]
331 // static DECLS: &[ProcMacro] = &[
332 // ProcMacro::custom_derive($name_trait1, &[], ::$name1);
333 // ProcMacro::custom_derive($name_trait2, &["attribute_name"], ::$name2);
338 cx: &mut ExtCtxt<'_>,
339 custom_derives: &[ProcMacroDerive],
340 custom_attrs: &[ProcMacroDef],
341 custom_macros: &[ProcMacroDef],
343 let span = DUMMY_SP.fresh_expansion(ExpnId::root(), ExpnInfo::allow_unstable(
344 ExpnKind::Macro(MacroKind::Attr, sym::proc_macro), DUMMY_SP, cx.parse_sess.edition,
345 [sym::rustc_attrs, sym::proc_macro_internals][..].into(),
348 let hidden = cx.meta_list_item_word(span, sym::hidden);
349 let doc = cx.meta_list(span, sym::doc, vec![hidden]);
350 let doc_hidden = cx.attribute(span, doc);
352 let proc_macro = Ident::with_empty_ctxt(sym::proc_macro);
353 let krate = cx.item(span,
356 ast::ItemKind::ExternCrate(None));
358 let bridge = Ident::from_str("bridge");
359 let client = Ident::from_str("client");
360 let proc_macro_ty = Ident::from_str("ProcMacro");
361 let custom_derive = Ident::from_str("custom_derive");
362 let attr = Ident::from_str("attr");
363 let bang = Ident::from_str("bang");
364 let crate_kw = Ident::with_empty_ctxt(kw::Crate);
367 let local_path = |sp: Span, name| {
368 cx.expr_path(cx.path(sp.with_ctxt(span.ctxt()), vec![crate_kw, name]))
370 let proc_macro_ty_method_path = |method| cx.expr_path(cx.path(span, vec![
371 proc_macro, bridge, client, proc_macro_ty, method,
373 custom_derives.iter().map(|cd| {
374 cx.expr_call(span, proc_macro_ty_method_path(custom_derive), vec![
375 cx.expr_str(cd.span, cd.trait_name),
378 cd.attrs.iter().map(|&s| cx.expr_str(cd.span, s)).collect::<Vec<_>>()
380 local_path(cd.span, cd.function_name),
382 }).chain(custom_attrs.iter().map(|ca| {
383 cx.expr_call(span, proc_macro_ty_method_path(attr), vec![
384 cx.expr_str(ca.span, ca.function_name.name),
385 local_path(ca.span, ca.function_name),
387 })).chain(custom_macros.iter().map(|cm| {
388 cx.expr_call(span, proc_macro_ty_method_path(bang), vec![
389 cx.expr_str(cm.span, cm.function_name.name),
390 local_path(cm.span, cm.function_name),
395 let decls_static = cx.item_static(
397 Ident::from_str("_DECLS"),
399 cx.ty(span, ast::TyKind::Slice(
400 cx.ty_path(cx.path(span,
401 vec![proc_macro, bridge, client, proc_macro_ty])))),
402 None, ast::Mutability::Immutable),
403 ast::Mutability::Immutable,
404 cx.expr_vec_slice(span, decls),
406 let attr = cx.meta_word(span, sym::rustc_proc_macro_decls);
407 i.attrs.push(cx.attribute(span, attr));
408 i.vis = respan(span, ast::VisibilityKind::Public);
412 let module = cx.item_mod(
415 ast::Ident::from_str("decls").gensym(),
417 vec![krate, decls_static],
419 i.vis = respan(span, ast::VisibilityKind::Public);
423 cx.monotonic_expander().flat_map_item(module).pop().unwrap()